The deterioration of reinforced concrete structures in
marine environments presents multiple problems due to the premature degradation
of reinforced steel. The corrosion of reinforcing steel exposed to seawater has
received significant attention due to its widespread use in industrial and
social infrastructures. This work aimed to study the corrosion of reinforced
A630-420H steel when exposed to a 0.5 M NaCl solution. Although this carbon
steel is the most widely used material for reinforced concrete structures in
Chile, there is limited research on its resistance to corrosion when in contact
with saline solutions. The electrochemical reactions and their roles in the
corrosion rate were studied using linear sweep voltammetry, weight loss,
scanning electron microscopy, and X-ray diffraction techniques. The
experimental procedure was designed to examine the kinetics of the partial
electrochemical reactions in A630-420H steel immersed in 0.5 M NaCl solution,
with a focus on the hydrogen evolution reaction (HER), oxygen reduction
reaction (ORR), and iron oxidation reaction (IOR). This analysis is unique as
it used the superposition model based on mixed potential theory to determine
the electrochemical and corrosion parameters. The outcomes of this study show
that A630-420H steel has a higher corrosion rate than those of the other
commercial carbon steels studied. This fact can be attributed to the
competition between the cathodic oxygen reduction reaction and hydrogen
evolution reaction, which also depends on the environmental conditions,
exposure time, stabilization of the corrosion products layer, and presence of
chloride ions. Additionally, the results under mechanical stress conditions
show a brittle fracture of the corrosion product oriented longitudinally in the
direction of the bend section, where the presence of pores and cracks were also
observed. The corrosion products after corrosion were mainly composed of
magnetite and lepidocrocite oxide phases, which are in concordance with the
electrochemical results.
Author(s) Details:
Felipe M. Galleguillos Madrid,
Centro de Desarrollo Energético de Antofagasta, Universidad de
Antofagasta, Av. Universidad de Antofagasta 02800, Antofagasta 1271155, Chile.
Alvaro Soliz,
Departamento
de Ingeniería en Metalurgia, Universidad de Atacama, Av. Copayapu 485, Copiapó
1530000, Chile.
Luis Cáceres,
Departamento de Ingeniería Química y Procesos de Minerales,
Universidad de Antofagasta, Av. Universidad de Antofagasta 02800, Antofagasta
1271155, Chile.
Sebastian Salazar-Avalos,
Centro de Desarrollo Energético de Antofagasta, Universidad de
Antofagasta, Av. Universidad de Antofagasta 02800, Antofagasta 1271155, Chile.
Danny Guzmán,
Departamento de Ingeniería en Metalurgia, Universidad de Atacama,
Av. Copayapu 485, Copiapó 1530000, Chile.
Edelmira Gálvez,
Departamento
de Ingeniería Metalúrgica y Minas, Universidad Católica del Norte, Av. Angamos
610, Antofagasta 1270709, Chile.
Please see the link here: https://stm.bookpi.org/CICMS-V8/article/view/14092
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